In document processing devices that process a plurality of documents one at a time, on occasion multifeeds occur. Multifeeds are the overlapping of sheets, pages, documents, or like articles that are transported through a respective document processing device. Conventionally, when such a multifeed occurs and is detected, an alarm will sound and/or operation of the document processing device will be halted.
Most multifeeds are unacceptable, e.g., in a scanner which will miss scanning part or all of a page when at least two pages are simultaneously fed. The inventors, however, have found that some multifeeds are acceptable, examples of which include a document which is affixed to another document, or special media in which documents detachably overlap. Other acceptable multifeed types are possible and are discussed further herein. When some multifeeds are acceptable, document process devices that trigger an alarm or halt production when even a multifeed is detected degrade throughput because they require a user to check and confirm whether or not each and every multifeed is acceptable.
What is needed is a document processing device that allows for acceptable multifeeds to occur, to increase document processing throughput, but still trigger an alarm for unacceptable multifeeds.